Scalable Terrain Rendering Data Management Infrastructure Ricardo Veguilla March 7, 2007

Ricardo Veguilla, UPRM Overview Goal [Ideal Terrain Rendering System] Problem [Performance] Solutions [GPUs,Level-of-detail,Out-of- core operation, Data streaming] The Big Picture [A Diagram] What is missing? [My Thesis]

Ricardo Veguilla, UPRM Goal – Ideal Terrain Rendering System Interactive [real-time rendering driven by user input] Accurate [complex geometry and high-resolution images] Scalable [rendering performance independent of hardware capabilities and data set size]

Ricardo Veguilla, UPRM Problem – Performance In general, interactive 3D rendering is computationally intensive. Terrain rendering introduces additional performances issues.

Ricardo Veguilla, UPRM Problem – Performance (cont) Accurate 3D rendering requires using detail and complex geometry as well as high-resolution images. Increased computational cost Increased data storage requirements

Ricardo Veguilla, UPRM Problem – Performance (cont) The interactive rendering of complex geometry using consumer-level PC hardware is currently feasible by exploiting GPU hardware and by employing Level of Detail rendering techniques.

Ricardo Veguilla, UPRM Problem – Performance (cont) GPUs allow improved rendering performance by the used of specialized hardware. Level-of-detail allow improved rendering by regulating the amount of detail used during the rendering.

Ricardo Veguilla, UPRM Problem – Performance (cont) Increase in main memory and disk storage capacity in consumer-level PC partially alleviates the data storage needs required for accurate terrain visualization.

Ricardo Veguilla, UPRM Problem – Performance (cont) Out-of-core operation allow working with data sets that surpass main memory capacity. Data streaming techniques allow working with data sets that surpass disk storage capacity.

Ricardo Veguilla, UPRM Solutions - GPUs Specialized programmable hardware optimized for 3D rendering operations. Maximizing GPU utilization requires continuously streaming data into the GPU memory.

Ricardo Veguilla, UPRM Solutions – GPUs (cont) Limitations: Not all PCs have GPUs Not all GPUs are created equal

Ricardo Veguilla, UPRM Solutions – Level of Detail Regulate geometric complexity and image resolution to used only the level of detail required for a particular situation (visual orientation, distance to the terrain, geometry complexity)

Ricardo Veguilla, UPRM Solutions – Level of Detail (cont) Requires maintaining a data structure in memory to manage multiple terrain representations at different level of detail, and performing a selection criteria to select which representation to use.

Ricardo Veguilla, UPRM Solutions – Level of Detail (cont) Different LOD techniques employ different data structures (generally trees) and employ different selection criteria as well as different simplification algorithms to produced the different terrain representations

Ricardo Veguilla, UPRM Solutions – Level of Detail (cont) LOD techniques may perform terrain simplification off-line (discrete), at run-time (continuous), or a combination of both.

Ricardo Veguilla, UPRM Solutions – Out-of-core Operations Data management scheme to support working with data larger than the available main memory. Requires maintaining a data structure to map terrain date segments to the actual data on disk.

Ricardo Veguilla, UPRM The Big Picture Main Memory Disk Storage GPU Memory Rendering Client Remote Data Server(s) Main Memory Disk Storage Full Data Representation Partial Data Representation Level of Detail Out-of-Core Data Streaming ? IO Barrier/Interface

Ricardo Veguilla, UPRM What is missing? (cont) Conceptual framework of the problem: Data characteristics Layer characteristic IO Barrier characteristics Data selection characteristics ?

Ricardo Veguilla, UPRM What is missing? (cont) What about embedded devices (smart phones and PDAs)? What about Web applications? Can we generalized for them too?

Ricardo Veguilla, UPRM References Jinzhu Gao, Jian Huang, C. Ryan Johnson, Scott Atchley, James Arthur Kohl, "Distributed Data Management for Large Volume Visualization," vis, p. 24, Pouderoux, J. and Marvie, J., “Adaptive streaming and rendering of large terrains using strip masks,” In Proceedings of the 3rd international Conference on Computer Graphics and interactive Techniques in Australasia and South East Asia (Dunedin, New Zealand, November 29 - December 02, 2005). GRAPHITE '05. ACM Press, New York, NY, Liqiang Zhang; Chongjun Yang; Suhong Liu; Yingchao Ren; Donglin Liu; Xiaoping Rui, “Effective techniques for interactive rendering of global terrain surfaces”, Geoscience and Remote Sensing Letters, IEEE, Vol.2, Iss.2, April 2005 Pages: Danovaro, E., De Floriani, L., Puppo, E., and Samet, H Multi-resolution out-of-core modeling of terrain and teological data. In Proceedings of the 13th Annual ACM international Workshop on Geographic information Systems (Bremen, Germany, November , 2005). GIS '05. ACM Press, New York, NY, Law, C. C., Martin, K. M., Schroeder, W. J., and Temkin, J. “A Multi-Threaded Streaming Pipeline Architecture for Large Structured Data Sets”. In Proceedings of the 10th IEEE Visualization 1999 Conference (VIS '99) (October , 1999). VISUALIZATION. IEEE Computer Society, Washington, DC, Beynon, M. D., Kurc, T., Sussman, A., and Saltz, J Design of a Framework for Data-Intensive Wide-Area Applications. In Proceedings of the 9th Heterogeneous Computing Workshop (May , 2000). HCW. IEEE Computer Society, Washington, DC, 116.

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